Vacuum Line Issues

i need a copy of the vacuum line scematic or a couple pics of the vacuum lines on your car for 91 ls. i think i got some switched and i cant get a book right now. i need them asap! thanks, harry

hey man do u have a picture of the way your lines are ?

i can try to take some pics later. but mainly i am concerned with the 3 lines that go on the hard lines on the pass side behind the im near the throttle body. one goes to the fuel charcoal canister?, one goes to a T that runs between my intake and something on the front of the intake, and the last one runs to the valve/diaphram that raise the throttle by vacuum. ill get pics so you know what im talking about. my car just wont idle at all and misses at low rpms. i am also going to try cleaning out my iacv and check my timing today.

There’s a diagram under your hood.

the hoods been changed out and its not there. i think im going to buy a book tomorow. thanks anyway.

My car was an automatic so disregard the EGR stuff if your car is a standard.

1991 LS as well.

yeah i got a printout for my car and all my lines were right but im sure i have a vacuum leak somewhere? maybe an o2 sensor or something? ill figure it out.

No “Thank You” for posting the picture?

thanks for posting your schematic. i got a similar one from a cd repair guide.


Generally, out of all the things listed in the diagram…which items tend to fail or need replacement the most?

The vacuum lines are pretty solid and don’t really carry a load so they rarely crack IMHO. I’ve never seen those solenoids fail but I have seen the MAP sensor go bad although that is rare.

I’d be more concerned about the small water lines to and from the IACV and FITV.